1. Field of the Invention
This invention relates to an artificial soil or soil improver suitable for rearing plants, particularly for decorative plants.
2. Description of the Prior Art
Heretofore, various artificial soils have been developed for decorative plants, and porous minerals such as vermiculite and pearlite have been utilized for the artificial soils.
On the other hand, the present inventors developed soils for rearing, plants composed of an inorganic or organic porous ion exchanger blended with at least one kind of porous inorganic materials such as vermiculite, pearlite and zeolite (Japanese Patent KOKAI No. 60-75209) and soil improvers composed of an inorganic or organic porous ion exchanger blended with slag wool (Japanese Patent KOKAI No. 61-91282), for use as soils which save labor for the maintenance of plants such as water supply and fertilization for a long period. In the above soils and soil improvers, water is held by the porous mineral such as vermiculite, pearlite, zeolite or slag wool, and fertilizer components are adsorbed on the ion exchanger. They are gradually released from the porous mineral or the ion exchanger according to their consumption, and supplied to the plants.
The above soils were placed in a water-impermeable bag, one made of a plastic sheet, in a planted state so as to prevent the evaporation of water in the atmosphere.
In general, mycorrhiza fungi live at the roots of plants. The mycorrhiza fungi supply nutrients such as minerals and vitamins to the plants, while the plants supply organic materials to the mycorrhiza fungi as a growth source. Therefore, both are in a symbiosis relationship. In the above soils placed in a water-impermeable bag, since the permeability of oxygen of the plastic sheet is low, the mycorrhiza fungi could not live because of insufficient oxygen.